Pest-controlling compostion

ABSTRACT

A pest-controlling composition comprised of a borate compound and a compound resulting in elevated concentrations of cyclic AMP, such as a phosphodiesterase enzyme (PDE) inhibitor, or a formamidine. The borate compound of the pest-controlling composition has increased toxicity as compared to a borate compound acting alone.

FIELD OF THE INVENTION

The present invention relates generally to a pest-controllingcomposition, and more particularly, to a pest-controlling compositioncomprised of a borate compound and a compound resulting in elevatedconcentrations of 3'-5'-cyclic adenosine monophosphate (cAMP).

BACKGROUND OF THE INVENTION

Compositions containing boron have long been used in the field of pestcontrol, particularly in insecticides. More recently, boron compoundshave declined in use due to the availability of modern syntheticinsecticides. However, there are several drawbacks associated withsynthetic insecticides, including resistance development in the pests,re-registration costs, and safety concerns by homeowners. These problemshave renewed interest in boron compounds for use in pest control.

Historically, the use of boron compounds in structural pest control hasbeen directed at cockroaches. More recently, research and developmenthas been aimed at the use of boron compounds (e.g., boric add) in thecontrol of ants, cockroaches, fleas, and wood-destroying organisms.

Among the pests most sought to be controlled are ants, cockroaches andfleas. With ants, if a bait is sufficiently attractive it will berapidly carried back to the ant nest and distributed to the entire antcolony. To effectively kill the ant colony, a slow-acting toxicant isrequired so that the ants have sufficient time to collect and distributethe insecticide before it reaches a lethal level.

In low concentrations, boric acid acts as a slow-acting toxicant. Oneadvantage to using boric acid to kill ants is its solubility in water.Not only is water a convenient carrier, but it also helps meet the ants'need for moisture their diet. Additionally, liquid baits exploit thenatural feeding habits of sweet-eating ants that collect honeydew,nectar and other plant juices. Another advantage of using boric acid tokill ants is that it acts like a desiccant (i.e., a substance thatremoves moisture), causing dehydration of the ants, which causes them toconsume more of the liquid bait.

With respect to control of cockroaches, boric acid has been usedprimarily as a stomach poison, either as a dust that is ingested by thecockroach during grooming, or as a toxicant incorporated into a bait.Only secondarily does the boric acid kill by contact. Traditionally, theconcentration of boric acid used in cockroach bait has been very high.In some cases, the bait may consist of 50% or more boric acid.

Boric acid is also useful in the control of fleas. In this regard, ithas been found that boric acid effectively controls fleas when appliedto the actively feeding larval stages of the fleas. Killing of thelarvae breaks the life cycle of the fleas, and leads to eventual controlof the flea population. The boric acid is believed to kill throughingestion since boric add appears to lack contact toxicity in fleas.

Among the problems encountered with the use of borates (e.g., boric acidor triethyl borate) as a pest-controlling composition is that boratesare relatively slow acting and lack potency. Accordingly, prior artpest-controlling compositions use high concentrations of borates.However, the use of increased borate concentrations has numerousdrawbacks. In this regard, there is a potential for bait avoidance bythe pests. For instance, fire ants are known to avoid ant baits having aborate content of 1% or more. Furthermore, high borate concentrationsalso pose a hazard to the environment. In this respect, borates aretoxic or injurious, to plants (i.e., phytotoxic). Moreover, theincreased borate concentrations may also threaten customer safety. Theprior art fails to provide a pest-controlling composition using boratecompounds in low concentrations, and which also provides quick andeffective pest control.

The present invention overcomes these and other drawbacks of usingborate compounds in a pest-controlling composition.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a pest-controllingcomposition comprising a borate compound containing oxygen and acompound resulting in elevated concentrations of 3'-5'-cyclic adenosinemonophosphate (cAMP).

It is an object of the present invention to provide a pest-controllingcomposition that increases the toxicity of borate compounds, thusallowing the use of lower borate compound concentrations in thepest-controlling composition and still yielding fast and effective pestcontrol.

It is another object of the present invention to provide apest-controlling composition having an increased toxicity of boratecompounds over the toxicity of borate compounds used alone at the sameconcentration.

It is still another object of the present invention to provide apest-controlling composition including a borate compound having anincreased toxicity at a lower concentration of borate compound.

Another object of the present invention is to provide a pest-controllingcomposition having a borate compound, which reduces or eliminates baitavoidance.

These and other objects will become apparent from the followingdescription of a preferred embodiment taken together with theaccompanying drawings and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described below with reference to testresults for insecticidal bait compositions for controlling cockroaches.However, it should be appreciated that it is contemplated that thepresent invention is effective for controlling other insect pests, suchas ants (e.g., carpenter, fire, ghost, pyramid, pharaoh, crazy and"pavement" ants), fleas, ticks, and the like, as well as non-insectpests (e.g., rodents).

3'-5'-cyclic adenosine monophosphate (hereinafter referred to as "cAMP"or "cyclic AMP") is a nucleotide found in almost all animal tissues(vertebrate and invertebrate) and in bacteria. Cyclic AMP is composed ofphosphate, ribose sugar and adenine. It is synthesized from ATP(adenosine triphosphate) in living cells by a reaction catalyzed by anenzyme called adenylate cyclase, which appears to be built into the cellmembrane. It has been discovered that substances that prevent thebreakdown of cAMP, and substances which increase the production of cAMPwill increase the toxicity of borate compounds to the pest, as comparedto the toxicity of borate compounds used alone.

Many, if not all cells of plants, animals, and microbes (exceptviruses), have a "second messenger" system which allow the cells to takesome external signal or message and convert that signal into some sortof response by the cell. One such "second messenger" system generatescAMP as a "second messenger." An extracellular "first messenger" goes toa target cell and there stimulates production of an intracellular"second messenger" which is cAMP. More specifically, the binding of the"first messenger" to a highly specific receptor site on the outersurface of the target cell activates the enzyme adenylate cyclase, whichcatalyzes production of more cAMP on the inner surface of the cellmembrane. The increased amounts of cAMP then initiate the cell'scharacteristic responses to the "first messenger." In particular, theincreased amounts of cAMP interact with cytoplasmic enzyme systems. Inthis regard, cAMP actuates a protein kinase enzyme, which in turnactivates certain enzymes and inactivates others by phosphorylatingthem. In summary, the initial extracellular signal (the "firstmessenger") is converted into an intracellular signal (cAMP, or "secondmessenger") that the chemical machinery of the cell can more readilyunderstand.

There are several signals (i.e., "first messengers") which will causeadenylate cyclase to produce cAMP, depending on the purpose of the cell.For instance, cells which respond to the neurochemical octopamine("first messenger") do so by having receptor sites for octopamine on theouter surface of the cell. When octopamine binds to this externalreceptor, the receptor (i.e., a protein which spans the cell membrane)causes the internal enzyme, adenylate cyclase, to produce cAMP. WhilecAMP production is linked to octopamine in octopamine-sensitive cells,this "second messenger" system for producing cAMP is not unique tooctopamine-sensitive cells. In this respect, borate compounds areunderstood to cause adenylate cyclase to produce cAMP, to prevent cAMPbreakdown, or to exacerbate the effects of elevated cAMP, in cells whichare not sensitive to octopamine. Accordingly, borate compounds are notdependent on octopamine-sensitive cells for effectiveness.

To prevent excessive responses by cells, the cells also containphosphodiesterase enzymes (PDE) which break down cAMP. An excess of cAMPwill be produced if the action of the PDE are blocked. Examples ofsubstances which inhibit the production of PDE include methylxanthines(such as caffeine and theophylline), papaverine, and other compounds.

It will also be appreciated that there are also substances which willincrease the production of cAMP, either directly or indirectly. Forexample, formamidines, such as chlordimeform (CDM) and Amitraz, increasethe production of cAMP. These compounds elevate cAMP production viaoctopamine agonist action.

Substances which inhibit the breakdown of cAMP (i.e., PDE inhibitors)and substances which increase the production of cAMP (e.g.,formamidines), will increase the toxicity to pests of borate compoundsover the toxicity of the borate compounds used alone. The inverse isalso true, in that borate compounds will increase the toxicity ofsubstances which inhibit PDE production and substances which elevatecAMP.

The combination of borate compounds and PDE inhibitors (or substanceswhich increase cAMP production) results in the correlated action of bothcompounds which, together, have greater total effect than the sum oftheir individual effects. Accordingly, a synergistic effect is obtainedwhen using a borate compound with a PDE inhibitor or a compound whichincreases cAMP production.

It should be understood that the term "borate compounds" is used hereinto refer to any trivalent borate compound containing oxygen attached toboron.

As will be discussed below, mixtures of borate compounds with PDEinhibitors, or substances which increase cAMP production, will shortenthe "time to death" of the pests (e.g., cockroaches) over the "time todeath" of the borate compounds used alone. Use of a PDE inhibitor or asubstance increasing cAMP production will increase the action andpotency of the borate compounds by increasing their toxicity.Accordingly, the time needed to kill the targeted pests with thecombined substances will be reduced relative to the time needed to killthe targeted pests with the borate compound alone. Due to the increasedtoxicity of the borate compounds when used with a PDE inhibitor or asubstance increasing cAMP production, the concentrations of boratecompounds can be lowered in a pest-controlling composition, while stillmaintaining the composition's speed and effectiveness.

Several benefits are obtained by lowering the borate compoundconcentration needed to control the pests. Among these benefits arereduction or elimination of bait avoidance, which is a particularproblem with respect to fire ants, which typically avoid ant bait havinga concentration of 1% or more of borate compounds. Moreover, thephytotoxicity of the pest-controlling composition is reduced, thusminimizing environmental problems. In addition, consumer safety isenhanced by a reduction in the borate compound concentration.

According to a preferred embodiment of the present invention, thepest-controlling composition is comprised of a borate compound and acompound resulting in an elevated concentration of cAMP. For instance,the borate compound may be boric acid or triethyl borate. The compoundresulting in elevated concentrations of cAMP may be a PDE inhibitor or aformamidine. For instance, the PDE inhibitor may be a methlxanthine(such as caffeine, theophylline, or dibutyrl cyclic AMP) or papaverine.Examples of suitable formamidines include chlordimeform (CDM) andAmitraz.

In a preferred embodiment of the invention, the pest-controllingcomposition is comprised of boric acid and caffeine. Caffeine is apreferred PDE inhibitor because it is already a government approved foodadditive, is relatively inexpensive, and is readily available. Caffeineis the least likely of the PDE inhibitors to cause regulatory problems.In this regard, caffeine is used in numerous foods, used in several drugformulations, and sold over the counter as an appetite suppressant andsleep suppressant. As to cost, reagent grade caffeine costsapproximately $41.00 per kilogram, or approximately $16.00 per kilogramin wholesale bulk. These costs compare very favorably to the costsassociated with other PDE inhibitors.

Papaverine is a "natural product" found in opium. In the past, it hasbeen synthesized and used as a smooth muscle relaxant. However, whilepapaverine is an excellent borate synergist, it is more costly thancaffeine and may pose greater government regulatory problems thancaffeine.

It should be appreciated that the pest-controlling composition accordingto the present invention may include a borate compound with both a PDEinhibitor and a formamidine (such as CDM). As discussed above, a PDEinhibitor prevents the breakdown of cAMP, while formamidines increasecAMP production. These compounds will therefore act synergistically whenused with a borate compound. In this respect, the killing power ofcombined use of the borate compound and either a PDE inhibitor orformamidine is much greater than the sum of the killing power of theborate compound and the PDE inhibitor or formamidine used separately.Moreover, this embodiment of the invention provides a pest-controllingcomposition which will effect cells with octopamine receptors, as wellas cells without octopamine receptors.

Tables I-IV set forth below provide a series of test results conductedon adult male German cockroaches. It should be noted that all mortalitytest results were corrected using Abbott's formula in accordance withstandard toxicological practice. The "toxin" is the primary compound forkilling the roaches, while the "synergist" is the compound that causes asynergistic effect. However, as will be seen from the test results, thetoxin also acts as a synergist. Accordingly, the toxin and the synergistare actually

                                      TABLE i                                     __________________________________________________________________________                                 Lethal Time                                                                   (in hours)                                                                    For 50%                                          Test    Bait         Bait    Kill  Synergism                                  No.                                                                              Toxin                                                                              Form                                                                             Percentage                                                                         Synergist                                                                          Form                                                                             Percentage                                                                         (LT-50)                                                                             Ratio                                      __________________________________________________________________________    1  boric acid                                                                         liquid                                                                           0.19 --   -- --   191   1                                             boric acid                                                                         liquid                                                                           0.19 caffeine                                                                           liquid                                                                              0.97                                                                            120   1.59                                       2  boric acid                                                                         liquid                                                                           0.31 --   -- --   125   1                                             boric acid                                                                         liquid                                                                           0.31 caffeine                                                                           solid                                                                            2    80    1.56                                          caffeine                                                                           solid                                                                            2.00 --   -- --   367   --                                         3  boric acid                                                                         liquid                                                                           0.62 --   -- --   74    1                                             boric acid                                                                         liquid                                                                           0.62 caffeine                                                                           solid                                                                              0.8                                                                              61    1.21                                          boric acid                                                                         liquid                                                                           0.62 caffeine                                                                           solid                                                                            2    45    1.66                                          caffeine                                                                           solid                                                                            2.00 --   -- --   367   --                                         4  boric acid                                                                         solid                                                                            0.10 --   -- --   no kill                                                                             --                                            boric acid                                                                         solid                                                                            0.10 caffeine                                                                           solid                                                                            2    268   --                                            boric acid                                                                         solid                                                                            0.10 papaverine                                                                         liquid                                                                           1    82    --                                            papaverine                                                                         liquid                                                                           1.00 --   -- --   193   --                                            caffeine                                                                           solid                                                                            2.00 --   -- --   367   --                                         5  boric acid                                                                         solid                                                                            0.20 --   -- --   no kill                                                                             --                                            boric acid                                                                         solid                                                                            0.20 caffeine                                                                           solid                                                                            2    172   --                                            boric acid                                                                         solid                                                                            0.20 papaverine                                                                         liquid                                                                           1    95    --                                            papaverine                                                                         liquid                                                                           1.00 --   -- --   193   --                                            caffeine                                                                           solid                                                                            2.00 --   -- --   367   --                                         6  boric acid                                                                         solid                                                                            0.40 --   -- --   no kill                                                                             --                                            boric acid                                                                         solid                                                                            0.40 caffeine                                                                           solid                                                                            1    502   --                                            boric acid                                                                         solid                                                                            0.40 caffeine                                                                           solid                                                                            2    293   --                                            boric acid                                                                         solid                                                                            0.40 papaverine                                                                         liquid                                                                           1    71    --                                            papaverine                                                                         liquid                                                                           1.00 --   -- --   193   --                                            caffeine                                                                           solid                                                                            2.00 --   -- --   367   --                                         7  boric acid                                                                         solid                                                                            1.00 --   -- --   335   1                                             boric acid                                                                         solid                                                                            1.00 caffeine                                                                           solid                                                                            1    191   1.75                                          boric acid                                                                         solid                                                                            1.00 caffeine                                                                           solid                                                                            2    123   2.73                                          boric acid                                                                         solid                                                                            1.00 papaverine                                                                         liquid                                                                           1    89    3.77                                          papaverine                                                                         liquid                                                                           1.00 --   -- --   193   --                                            caffeine                                                                           solid                                                                            2.00 --   -- --   367   --                                         8  boric acid                                                                         solid                                                                            3.00 --   -- --   87    1                                             boric acid                                                                         solid                                                                            3.00 papaverine                                                                         liquid                                                                           1    56    1.56                                          papaverine                                                                         liquid                                                                           1.00 --   -- --   193   --                                         9  boric acid                                                                         solid                                                                            6.00 --   -- --   115   1                                             boric acid                                                                         solid                                                                            6.00 papaverine                                                                         liquid                                                                           1    64    1.80                                          papaverine                                                                         liquid                                                                           1.00 --   -- --   193   --                                         10 boric acid                                                                         solid   --   -- --   91    1                                             boric acid                                                                         solid                                                                            8.00 caffeine                                                                           solid                                                                            8    46    1.98                                          caffeine                                                                           solid                                                                            8.00 --   -- --   166   --                                         __________________________________________________________________________

                                      TABLE II                                    __________________________________________________________________________                 Lethal Dose                                                                   (in percentage)                                                  Hours    Bait                                                                              For 50% Kill                                                                              Bait     Synergism                                   Dosed                                                                             Toxin                                                                              Form                                                                              (LD-550)                                                                             Synergist                                                                          Form                                                                              Percentage                                                                         Ratio                                       __________________________________________________________________________    144 boric acid                                                                         solid                                                                             4.25   --   --  --   1                                           144 boric acid                                                                         solid                                                                             2.19   caffeine                                                                           solid                                                                             1    1.94                                        144 caffeine                                                                           solid                                                                             5.98   --   --  --   --                                          __________________________________________________________________________

                                      TABLE III                                   __________________________________________________________________________               Mass (in                                                                      micrograms per                                                                       Hours                                                                  gram of roach)                                                                       Pretreated                                                  Hours      for 50% Kill                                                                         with      Bait     Synergism                                Dosed                                                                             Toxin                                                                            Form                                                                              (LD-50)                                                                              Synergist                                                                          Synergist                                                                          Form                                                                              Percentage                                                                         Ratio                                    __________________________________________________________________________    48  CDM                                                                              topical                                                                           34.7   --   --   --  --   1                                        48  CDM                                                                              topical                                                                           12.7   4    boric acid                                                                         liquid                                                                            0.62 2.72                                     48  CDM                                                                              topical                                                                           9.18   24   boric acid                                                                         liquid                                                                            0.31 3.78                                     48  CDM                                                                              topical                                                                           9.53   48   boric acid                                                                         liquid                                                                            0.19 3.64                                     __________________________________________________________________________

                                      TABLE IV                                    __________________________________________________________________________                   Mass (in                                                                      micrograms per  Mass (in                                                      grams of roach  microgram                                      Hours          for 50% Kill    per gram                                                                           Synergism                                 Dosed                                                                             Toxin  Form                                                                              (LD-50)                                                                              Synergist                                                                          Form                                                                              of Roach)                                                                          Ratio                                     __________________________________________________________________________    48  triethyl borate                                                                      topical                                                                           526    --   --  --   1                                         48  triethyl borate                                                                      topical                                                                           166    Amitraz                                                                            topical                                                                           10   3.16                                      __________________________________________________________________________

                                      TABLE V                                     __________________________________________________________________________          Bait           Bait     Ratio of                                                                          Ratio of                                    Compound                                                                            Form                                                                              Percentage                                                                         Compound                                                                            Form                                                                              Percentage                                                                         C to B                                                                            B to C                                      __________________________________________________________________________    boric acid                                                                          liquid                                                                            0.1% caffeine                                                                            liquid                                                                            2.0% 20  0.05                                        boric acid                                                                          liquid                                                                            1.0% caffeine                                                                            liquid                                                                            0.5% 0.5 2                                           boric acid                                                                          solid                                                                             0.1% caffeine                                                                            solid                                                                             2.0% 20  0.05                                        boric acid                                                                          solid                                                                             10.0%                                                                              caffeine                                                                            solid                                                                             0.5% 0.05                                                                              20                                          __________________________________________________________________________

Referring now to Table I, it should be noted that where the "bait form"is indicated as "liquid," the respective compound (i.e., the toxin orsynergist) has been mixed with water. Furthermore, the respectivepercentage refers to the weight of the compound per the total volume ofthe liquid bait. Similarly, where the "bait form" is indicated as"solid," the respective compound (i.e., the toxin or synergist) has beenwet mixed with rat chow and then dried. Furthermore, the respectivepercentage refers to the weight of the compound per the total weight ofthe solid bait. It will be appreciated that where the toxin compound isprovided in bait form different from the bait form of the synergistcompound, the toxin compound and synergist compound were provided to theroaches by a different bait source.

The term "LT-50" refers to the number of hours required to kill one-half(i.e., 50%) of the roaches. The synergism ratio shown in the last columnis provided to indicate improvements in killing power when a synergistis used. The synergism ratio is "1" for the toxin used effectively alonewithout a synergist. Subsequent synergism ratios are computed bydividing the LT-50 for the toxin used alone by the LT-50 for the toxinused with a synergist. A synergism ratio of "2" would indicate that atoxin used in combination with the synergist is twice as potent (orreduced the time to kill by one-half) than the toxin used alone. Itshould be noted that a synergism ratio cannot be computed when the toxinused alone is ineffective (i.e., there is "no kill"). In this regard,the term "no kill" means that no cockroaches were killed during thetesting period of over four weeks.

It can be seen from the tests shown in Table I that when caffeine orpapaverine is used as a synergist in combination with boric acid, thelethal time for killing 50% of the roaches (LT-50) is significantlylower than the LT-50 for boric acid used alone at the same concentrationor "percentage." Accordingly, lower concentrations of boric acid can beused, while obtaining improved LT-50 results. For instance, in Test No.6, when boric acid is used alone as a toxin at a percentage of 0.40%, noroaches are killed. In contrast, when the boric acid is used at the sameconcentration (i.e., 0.40%) with a caffeine synergist at 1%, the LT-50is 502 hours. When boric acid is again used at the same concentration(i.e., 0.40%) with a caffeine synergist at 2%, the LT-50 drops to 293hours. Moreover, when the boric acid is once again used at aconcentration of 0.40% with a papaverine synergist at 1%, the LT-50drops further to 71 hours.

Table I also illustrates that when caffeine or papaverine is used as asynergist in combination with boric acid, the LT-50 is significantlylower than the LT-50 for caffeine or papaverine used alone as the toxinin the same percentage concentration. For instance, in Test No. 4, whenboric acid is used as a toxin at 0.10%, with a caffeine synergist at 2%,the LT-50 is 268 hours. In contrast, when caffeine is used alone as atoxin at 2%, the LT-50 rises to 367 hours. Thus, the boric acidsynergizes the caffeine and papaverine.

Table II provides test results for a fixed number of hours in which theroaches are exposed to the bait. In this respect, mortality is assessed144 hours after dosing. The lethal dose for killing 50% of the roaches(LD-50) is determined for boric acid acting alone as a toxin, boric acidacting as a toxin with a caffeine synergist, and caffeine acting aloneas a toxin. As can be seen from Table II, when boric acid acts alone, itmust be used in a higher concentration to kill 50% of the roaches in a144-hour dosing period, than when boric acid is used with a caffeinesynergist. Similarly, when caffeine acts alone, it must be used in ahigher concentration to kill 50% of the roaches in a 144-hour dosingperiod, than when caffeine is used as a synergist with boric acid.

It should be noted that for each test in Table II the bait form is asolid. Accordingly, the compounds have been wet mixed with rat chow,then dried, and the percentages for the toxin and synergist refer to theweight of the toxin or synergist per the total weight of the solid bait.

Table III illustrates the effects of using boric acid with aformamidine. In the test shown, the formamidine is chlordimeform (CDM).However, it will be appreciated that other formamidines, such asAmitraz, are also suitable.

It should be understood that a "topical" form for the toxin means thatthe toxin is dissolved in acetone and then topically applied to theroaches (i.e., there is no bait). The mass of the toxin for the LD-50 isthe mass of the toxin only (i.e., does not include the acetone). Sincethe synergist bait form is a liquid, the synergist has been added towater, and the percentage of the synergist refers to the weight of thesynergist per the total volume of the liquid bait. Furthermore, itshould be understood that in the test shown in Table III, the roacheswere pretreated with the synergist before they were given the toxin. Thenumber of pretreatment hours is indicated. The column labeled "HoursDosed w/Toxin" refers to the number of hours the roaches were dosed withthe toxin after pretreatment with the synergist.

Table III shows that the mass of CDM needed to kill 50% of the roacheswhen using CDM alone is much greater than the mass of CDM needed to kill50% of the roaches when using CDM with a boric acid synergist.

Turning now to Table IV, this table is included to show how a boratecompound other than boric acid (i.e., triethyl borate), and aformamidine synergist (i.e., Amitraz) are also effective in controllingpests. As in Table III, the toxin is applied topically by dissolving thetoxin in acetone and topically applying it to the roaches (i.e., thereis no bait). Likewise, the synergist is applied topically. The massvalues for the toxin and synergist do not include the mass of theacetone. The toxin, triethyl borate, is applied topically becausetriethyl borate penetrates the roaches' cuticle and is believed to bebroken down internally by the roach to boric acid.

Table IV illustrates that the mass of triethyl borate needed to kill 50%of the roaches (LD-50), in 48 hours, is significantly greater than themass of triethyl borate needed to kill 50% of the roaches (LD-50), in 48hours, when used with Amitraz. The synergism ratio indicates that use ofthe Amitraz synergist makes the pest-controlling composition over threetimes more potent, while using a reduced amount of triethyl borate.

In view of the foregoing test results illustrated in Tables I-IV, apreferred pest-controlling composition for cockroaches and ants in theform of a liquid bait comprises approximately 0.1% to 1% boric acid andapproximately 0.5% to 2% caffeine. The foregoing percentages refer tothe weight of the compound per the total volume of the liquid bait. SeeTABLE V for the ratios corresponding to the foregoing percentages onboric acid and caffeine in a liquid bait.

More specifically, a preferred pest-controlling composition in liquidform for cockroaches or ants is 0.5% boric acid and 1% caffeine. Itshould be noted that there may be some repellency with fire ants at 0.5%boric acid, therefore, for ants, the boric acid may be lowered tobetween approximately 0.2% and 0.3%. Moreover, it should be understoodthat cockroaches may avoid percentages of caffeine that exceed much over1%.

The preferred pest-controlling composition for cockroaches and ants inthe form of a solid bait comprises approximately 0.1% to 10% boric acidand approximately 0.5% to 2% caffeine. The foregoing percentages referto the weight of the compound per the total weight of the solid bait.See TABLE V for the ratios corresponding to the foregoing percentages ofboric acid and caffeine in a solid bait.

For a preferred pest-controlling composition in solid form forcockroaches the composition preferably comprises 1.0% boric acid and1.0% caffeine. For ants, the preferred concentrations are 0.2% boricacid and 1.0% caffeine. The lower boric acid concentration for antsprovides a slow kill, which is more effective in wiping out the entirecolony. This contrasts with roach control where a fast kill is desirableto quickly eliminate the cockroaches.

While it is understood that liquid baits may include water and solidbaits may include a dry bait food (such as distillers grain or ratchow), the baits may also include an attractant such as sucrose, apreservative, pH controllers, an anti-oxidant and a mold inhibitor.

A preservative may be added to help preserve the toxin and synergist.With regard to pH controllers, it may be desirable to fix the pH levelto maintain quality control. In this respect, the pH level may affectthe action of the preservative, the action of the toxin and synergist,the shelf-life of the composition and the taste of the composition. Itshould be noted that a borate compound, such as boric acid, willprobably lower the pH level, while a PDE inhibitor, such as caffeine,will probably raise the pH level. A preferred pH level is approximately6.5. Hydrochloric acid and sodium hydroxide are examples of suitable pHcontrollers. An anti-oxidant may be added to keep the PDE inhibitor(i.e., caffeine) from breaking down through oxidation. The moldinhibitor is desirable to prevent the formation of mold during storageand use of the pest-controlling composition.

While a range of percentages has been provided above for apest-controlling composition suitable for controlling both ants andcockroaches, it should be understood that for controlling ants, thelower end of the boric acid range will likely be preferred. In thisregard, some species of ants (e.g., fire ants) may avoid high boric acidconcentration. Moreover, in controlling ants it is desirable to have aslow kill, so that the ants have an opportunity to feed the bait to thewhole colony, including the queen.

While the data set forth in Tables I-IV is for cockroaches, the resultswill be similar for ants. In this respect, caffeine should have, by allconventional scientific understanding, the same effect on ants as it hason cockroaches. In fact, as a group, ants are less able to detoxifychemicals. Therefore, the caffeine should be at least as effective onants as on the cockroaches. The data of Tables I-IV also suggests that aborate compound used with a compound resulting in elevatedconcentrations of cAMP would be effective in controlling other pests,including insects and non-insects. For other pests, however, theconcentrations of the toxins and synergists may vary from those setforth in the tables.

The foregoing description provides specific embodiments of the presentinvention. It should be appreciated that these embodiments are describedfor the purposes of illustration only, and that numerous alterations andmodifications may be practiced by those skilled in the art withoutdeparting from the spirit and scope of the invention. It is intendedthat all such modifications and alterations be included insofar as theycome within the scope of the invention as claimed or the equivalentsthereof.

What is claimed is:
 1. A composition for combating insects comprisingsynergistic effective amounts of:boric acid; and caffeine.
 2. Acomposition according to claim 1, wherein said insects are ants androaches, and wherein said composition is a liquid bait, and the weightratio of caffeine to boric acid is between approximately 2 and
 20. 3. Acomposition according to claim 1, wherein said composition is solidbait, and the weight ratio of caffeine to boric acid is betweenapproximately 0.05 and
 20. 4. A composition according to claim 1,wherein said composition is a liquid bait comprising by percentageweight per total bait volume:about 0.01% to 1% boric acid; and about0.5% to 2% caffeine.
 5. A composition according to claim 4, wherein saidcomposition comprises by percentage weight per total bait volume:about0.5% boric acid; and about 1% caffeine.
 6. A composition according toclaim 1, wherein said composition is a dry bait comprising by percentageweight per total bait weight:about 0.1% to 10% boric acid; and about0.5% to 2% caffeine.
 7. A composition according to claim 6, wherein saidcomposition comprises by percentage weight per total bait weight:about1% boric acid; and about 1% caffeine.
 8. A composition according toclaim 6, wherein said composition comprises by percentage weight pertotal bait weight:about 0.2% boric acid; and about 1% caffeine.